EP1058276A2 - Dünnschichtthermistor und Herstellungsverfahren - Google Patents

Dünnschichtthermistor und Herstellungsverfahren Download PDF

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EP1058276A2
EP1058276A2 EP00304729A EP00304729A EP1058276A2 EP 1058276 A2 EP1058276 A2 EP 1058276A2 EP 00304729 A EP00304729 A EP 00304729A EP 00304729 A EP00304729 A EP 00304729A EP 1058276 A2 EP1058276 A2 EP 1058276A2
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European Patent Office
Prior art keywords
thin film
thermistor
thermistor element
crystal structure
type crystal
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EP00304729A
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English (en)
French (fr)
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EP1058276A3 (de
EP1058276B1 (de
Inventor
Eiji Fujii
Atsushi Tomozawa
Hideo Torii
Ryoichi Takayama
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Panasonic Holdings Corp
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Matsushita Electric Industrial Co Ltd
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Priority claimed from JP15662699A external-priority patent/JP4279400B2/ja
Priority claimed from JP15670899A external-priority patent/JP4279401B2/ja
Priority claimed from JP15656999A external-priority patent/JP4279399B2/ja
Priority claimed from JP11161903A external-priority patent/JP2000348911A/ja
Priority claimed from JP25522599A external-priority patent/JP4277380B2/ja
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Publication of EP1058276A2 publication Critical patent/EP1058276A2/de
Publication of EP1058276A3 publication Critical patent/EP1058276A3/de
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/04—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having negative temperature coefficient
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C17/00—Apparatus or processes specially adapted for manufacturing resistors
    • H01C17/06—Apparatus or processes specially adapted for manufacturing resistors adapted for coating resistive material on a base
    • H01C17/075—Apparatus or processes specially adapted for manufacturing resistors adapted for coating resistive material on a base by thin film techniques
    • H01C17/12—Apparatus or processes specially adapted for manufacturing resistors adapted for coating resistive material on a base by thin film techniques by sputtering
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/02—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient
    • H01C7/022—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient mainly consisting of non-metallic substances
    • H01C7/023—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient mainly consisting of non-metallic substances containing oxides or oxidic compounds, e.g. ferrites
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
    • Y10T428/24802—Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]
    • Y10T428/24917—Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.] including metal layer

Definitions

  • the present invention relates to a thin film thermistor element (a thin film NTC thermistor element) for use in temperature sensors of a variety of equipment such as information processing equipment, communication equipment, housing-facility equipment, automobile electrical equipment, and to a method for the fabrication thereof.
  • a thin film thermistor element a thin film NTC thermistor element
  • An NTC thermistor element of oxide semiconductor material as an element for the detection of temperature is typically constructed by formation of an electrode (e.g., an electrode of Ag) on an end face of an oxide sintered body chip whose major component is a transition metal such as Mn, Co, Ni, and Fe and which has a spinel type crystal structure, by means of application or baking.
  • an electrode e.g., an electrode of Ag
  • an oxide sintered body chip whose major component is a transition metal such as Mn, Co, Ni, and Fe and which has a spinel type crystal structure
  • NTC thermistor elements have the following advantages over thermocouples and platinum resistance temperature sensors. Therefore, the NTC thermistor clement has currently been in wide use.
  • the NTC thermistor element is used not only to measure the temperature of an object but also to control a current in a power supply device.
  • the NTC thermistor element has the property that its resistance value is high at room temperature but decreases as the temperature rises. Because of such a property, the NTC thermistor element serves, for example, in a switching power supply, as an excessive current control element which controls an excessive current (i.e., an initial rush current) that starts flowing the instant the power supply switch is turned on and which thereafter becomes low in resistance with the rise of temperature by self exothermicity, whereby the loss of power is held low in the steady state.
  • an excessive current i.e., an initial rush current
  • NTC thermistor elements that find their way into such an application are fabricated from, for example, rare earth transition metal oxide as a thermistor material. More specifically, a sintered body of lanthanum cobalt oxide having a perovskite type crystal structure is used, wherein a thin film electrode of silver is formed atop the sintered body by means of sputtering (see Japanese Unexamined Patent Gazette No. H07-230902).
  • thermistor elements employing thin film technology for the formation of thermistor material and electrodes.
  • This type of thin film thermistor element is fabricated as follows. A thermistor thin film is formed by a sputtering technique targeting on a sintered body of complex oxide of, for example, Mn, Ni, Co, and Fe, which is followed by formation of a predefined electrode pattern on the thermistor thin film.
  • a thermistor thin film formed by sputtering suffers several problems.
  • thermistor thin film of spinel type oxide semiconductor formed by sputtering is crystal grown by heat treatment, it is likely that the variation in crystal grain diameter in the resulting polycrystalline substance is great. Because of this, even with regard to thermistor elements of the same fabrication lot, they vary considerably in electrical characteristic, e.g., the resistance value and the B constant. Moreover, even if heat treatment is carried out at, for example, 400 degrees centigrade or above, this will find difficulties in improving stability to a greater extent, and it is also difficult to improve high temperature durability.
  • an object of the present invention is to provide a thin film thermistor element capable of holding, for example, the variation in resistance value low for the achievement of high accuracy and capable of improving high temperature durability for the achievement of high reliability, and a method for the fabrication of such a thin film thermistor element.
  • the present invention provides a thin film thermistor element.
  • the thin film thermistor element of the present invention comprises a thermistor thin film and a pair of electrodes formed on the thermistor thin film, wherein the thermistor thin film has either a spinel type crystal structure which is oriented mainly in a (100) surface, a bixbite type crystal structure (particularly, a bixbite type crystal structure which is oriented mainly in a (100) or (111) surface), or a rhombohedral perovskite type crystal structure (particularly, a rhombohedral perovskite type crystal structure which is oriented mainly in (012).
  • a thermistor thin film having a spinel type crystal structure with a (100) surface orientation or bixbite type crystal structure can be formed of, for example, a thin film of oxide whose major component is manganese. Further, a thermistor thin film having a rhombohedral perovskite type crystal structure can be formed of, for example, a composition containing lanthanum cobalt oxide. Furthermore, it is preferred that a thermistor thin film having a spinel type crystal structure with a (100) surface orientation has a crystal grain which has grown by crystallization into a columnar shape in a direction perpendicular with respect to the thermistor thin film.
  • the above-described thermistor thin films of the present invention each show less variation in the crystal grain diameter in comparison with thermistors of a sintered body and thermistor thin films having a no-orientation spinel type crystal structure, because of which the variation in electrical characteristic (such as the resistance value and B constant (i.e., the change rate of resistance to temperature) can be held low and, in addition, the crystal state is relatively stable so that the deterioration with time of such electrical characteristics can be held low and the high temperature durability is high. Accordingly, with such a crystal structure, it becomes possible to achieve high-accuracy, high-reliability thermistor elements. Further, formation is carried out through the use of thin film technology, whereby down-sizing is easier to achieve in comparison with the case where a sintered body thermistor is employed.
  • Thermistor thin films of the type described above can be formed by alternately carrying out a film formation step by, for example, sputtering and an anneal step. More specifically, an arrangement is made, wherein at least either one of a substrate holder for holding a backing substrate and a target placed face to face with the substrate holder is rotated and wherein the backing substrate is held at a position eccentric from the center of the rotation in the substrate holder while the target is covered with a shield cover so that a part of a position eccentric from the rotational center in the target is exposed, whereby the film formation step by sputtering can be carried out on the backing substrate at a rotational position whereat the backing substrate faces the exposed portion of the target while on the other hand the anneal step can be carried out at a rotational position whereat the backing substrate faces the position of the target covered with the shield cover.
  • thermistor thin film of the type described above it is possible to form a higher-accuracy, higher-reliability thermistor element by performing a heat treatment after the formation of a thermistor thin film of the type described above, wherein the substrate temperature and the heat treatment temperature during the film formation by sputtering are set to various values according to the composition and the film formation time of a thermistor thin film that is formed.
  • a film formation step is carried out with a substrate heated to 200-600 degrees centigrade and a heat treatment is carried out in air at 600-1000 degrees centigrade, whereby the foregoing thermistor element can be fabricated easily.
  • thermistor thin film formation is carried out in an atmosphere in which the rate of flow between argon gas and oxygen gas is 3 or greater, this relatively facilitates formation of a thermistor thin film having a spinel type crystal structure with a (100) surface orientation, and if the heat treatment is carried out at 1100 degrees centigrade or below, this relatively facilitates formation of a thermistor thin film having a bixbite type crystal structure.
  • an electrode is provided with a trimming portion for the adjustment of resistance, and the trimming portion is cut using laser light irradiation or the like to make a resistance adjustment, whereby it becomes possible to facilitate the fabrication of higher-accuracy thin film thermistor elements.
  • FIGURE 1 is a perspective view illustrating a structure of a thin film thermistor element according to the present invention.
  • FIGURE 2 is a perspective view illustrating a structure of a device used to fabricate a thin film thermistor element according to the present invention.
  • FIGURE 3 is a perspective view illustrating a structure of another device used to fabricate a thin film thermistor element according to the present invention.
  • FIGURE 1 there is shown a thin film thermistor element 10 in which a thermistor thin film 12 and a pair of comb electrodes 13 and 14 comprising a thin film of Pt are formed on a backing substrate of alumina.
  • the thermistor thin film 12 is composed of, for example, complex oxide of Mn-Co-Ni that has a spinel type crystal structure which is priority oriented in a (100) surface, in other words which is oriented mainly in a (100) surface.
  • the comb electrode 13 has a base resistance portion 13a and a trimming portion 13b
  • the comb electrode 14 has a base resistance portion 14a and a trimming portion 14b.
  • Each base resistance portion 13a and 14a is for setting the resistance of the thin film thermistor element 10 roughly to a target value.
  • each trimming portion 13b and 14b is for making fine adjustment so as to obtain resistance values at predefined accuracy. Such resistance value fine adjustment will be discussed later in detail.
  • the thermistor thin film 12 of the foregoing type can be fabricated using, for example, a sputter device 21 as shown in FIGURE 2.
  • a substrate holder 22 for supporting the backing substrate 11 and a sintered body target 23 of, for example, complex oxide formed of Mn-Co-Ni having a diameter of 8 inches are mounted face to face with each other at an interval of 50 mm.
  • the sintered body target 23 is covered with a shield cover 24 having a notch 24a whose central angle is 90 degrees in such a way that a part of the sintered body target 23 is exposed.
  • Coupled to the sintered body target 23 is a high frequency power supply 25 (13.56 MHz).
  • the substrate holder 22 is rotated by a drive device (not shown in the figure) at a predefined rotational speed.
  • Both the substrate holder 22 and the sintered body target 23 are placed in a chamber (not shown in the figure) filled with, for example, a mixed gas of argon and oxygen.
  • the substrate holder 22 With the backing substrate 11 held by the substrate holder 22, heating is carried out, and the substrate holder 22 is rotated at a predefined rotational speed while at the same time a high frequency voltage is applied to the sintered body target 23. At the time when the backing substrate 11 passes over the notch 24a of the shield cover 24, grains flying from the sintered body target 23 are sputtered to form the thermistor thin film 12. On the other hand, at the time when the backing substrate 11 passes over the shield cover 24, the thermistor thin film 12 is oxidized and annealed. In other words, sputtering, oxidation, and anneal are carried out alternately for the formation of the thermistor thin film 12.
  • the rotating of the substrate holder 22 is one possible way and another possible way is to dispose a shield plate extendably and retractably between the substrate holder 22 and the sintered body target 23.
  • the thermistor thin film 12 thus formed is subjected to heat treatment at a predefined temperature.
  • the resulting thermistor thin film 12 has a spinel type crystal structure which is oriented mainly in a (100) surface, being even in crystal grain diameter.
  • the formation conditions of the thermistor thin film 12 i.e., the condition of sputtering and the condition of heat treatment
  • the formation conditions of the thermistor thin film 12 i.e., the condition of sputtering and the condition of heat treatment
  • thermoistor thin films 12 were formed under conditions as shown in TABLE 1. Then, these thermistor thin films 12 thus formed were subjected to heat treatment in air under conditions as shown in the table.
  • the major difference between EXPERIMENTAL EXAMPLE (A1-A8) and COMPARE EXAMPLE (A1-A8) is the presence or absence of rotation of the substrate holder 22.
  • EXPERIMENTAL EXAMPLES A1-A8 as describe above, sputtering and oxidation/anneal are carried out alternately, while on the other hand in COMPARE EXAMPLES A1-A8 sputtering is carried out continuously without the provision of the shield cover 24.
  • alumina substrates sized to have dimensions of 50 mm ⁇ 50 mm ⁇ 0.3 mm and polished to such an extent that their surface irregularity fell below 0.03 ⁇ m, were used as the backing substrate 11.
  • the substrate holder 22 was made to hold, in addition to the backing substrate 11, a glass substrate 31 for the purpose of evaluating crystallinity.
  • the X ray diffraction analysis shows that the thermistor thin films 12 after the heat treatment in EXPERIMENTAL EXAMPLES A1-A8 each have a spinel type crystal structure which is oriented mainly in a (100) surface, while on the other hand the thermistor thin films 12 of COMPARE EXAMPLES A1-A8 each have a spinel type crystal structure which is oriented at random (showing no crystal orientation property).
  • a thin film of Pt having a thickness of 0.1 ⁇ m and a resist pattern were formed all over the surface of the thermistor thin film 12 formed on the backing substrate 11 and then heat treated. This was followed by patterning by means of a photolithography technique using dry etching with Ar (argon gas) thereby to form the comb electrodes 13 and 14. Then, a dicing device was used to cut, at a size of 1 ⁇ 0.5 mm, the backing substrate 11 (except its periphery) to prepare 1000 individual thin film thermistor elements 10 having a structure as shown in FIGURE 1 and their respective resistance values and B constants (the change rate of resistance to temperature) were measured to find average values and variations ((maximum value - minimum value)/average value).
  • any other thermistor thin films as long as they have a spinel type crystal structure which is oriented mainly in a (100) surface, likewise produced good results even when using a complex oxide composition different from the ones shown in TABLE 2.
  • the formation condition and the heat treatment condition of thermistor thin films are not limited to the conditions shown in the table and can therefore be set in various ways according to the composition of sintered body targets.
  • the oxygen partial pressure is generally low and when the argon/oxygen flow rate is three or greater, this facilitates the formation of a spinel type crystal structure which is oriented mainly in a (100) surface.
  • any other one that partially contains a bixbite type crystal phase or an NaCl type crystal phase in a spinel type crystal phase, can be applicable. Further, even when there exists a layer on the thermistor thin film surface that is oriented to a different crystal face, what is required is that the inside of the thermistor thin film is substantially oriented in a (100) surface.
  • the ratio of the peak value according to the foregoing crystal structure to the sum of peak values according to crystal structures in X ray diffraction is roughly 50% or greater (preferably 75% or greater), this will contribute to providing good characteristics (with regard to the peak value ratio, the same will be applied to the following embodiments of the present invention).
  • the thin film thermistor element 10 of the second embodiment has apparently the same structure as the first embodiment (see FIGURE 1) but differs from the first embodiment in that the thermistor thin film 12 is formed of, for example, complex oxide of Mn-Co-Ni having a bixbite type crystal structure.
  • the thermistor thin film 12 of such a type can be formed by, for example, the sputter device 21 shown in FIGURE 2, as in the first embodiment.
  • the formation conditions of the thermistor thin film 12 i.e., the condition of sputtering and the condition of heat treatment
  • the formation conditions of the thermistor thin film 12 i.e., the condition of sputtering and the condition of heat treatment
  • thermistor thin films 12 were formed under conditions as shown in TABLE 3. Then, these thermistor thin films 12 thus formed were subjected to heat treatment in air under conditions as shown in the table.
  • the major difference between EXPERIMENTAL EXAMPLE (B1-B8) and COMPARE EXAMPLE (B1-B8) is the presence or absence of rotation of the substrate holder 22.
  • EXPERIMENTAL EXAMPLES B1-B8 as describe above, sputtering and oxidation/anneal are carried out alternately, while on the other hand in COMPARE EXAMPLES B1-B8 sputtering is carried out continuously without the provision of the shield cover 24.
  • alumina substrates sized to have dimensions of 50 mm ⁇ 50 mm ⁇ 0.3 mm and polished to such an extent that their surface irregularity fell below 0.03 ⁇ m, were used as the backing substrate 11.
  • the substrate holder 22 was made to hold, in addition to the backing substrate 11, a glass substrate 31 for the purpose of evaluating crystallinity.
  • the X ray diffraction analysis shows that the thermistor thin films 12 after the heat treatment in EXPERIMENTAL EXAMPLES B1-B8 each have a bixbite type crystal structure, while on the other hand the thermistor thin films 12 of COMPARE EXAMPLES B1-B8 each have a spinel type crystal structure.
  • EXPERIMENTAL EXAMPLES B1-B8 each have a priority orientation in a (100) surface
  • EXPERIMENTAL EXAMPLES B4, B6, and B8 each have a priority orientation in a (111) surface
  • neither EXPERIMENTAL EXAMPLE B1 nor EXPERIMENTAL EXAMPLE B7 shows any priority orientation, in other words, they are random in orientation.
  • a thin film of Pt having a thickness of 0.1 ⁇ m and a resist pattern were formed all over the surface of the thermistor thin film 12 formed on the backing substrate 11 and then heat treated. This was followed by patterning by means of a photolithography technique using dry etching with Ar (argon gas) thereby to form the comb electrodes 13 and 14. Then, a dicing device was used to cut, at a size of 1 ⁇ 0.5 mm, the backing substrate 11 (except its periphery) to prepare 1000 individual thin film thermistor elements 10 having a structure as shown in FIGURE 1 and their respective resistance values and B constants (the change rate of resistance to temperature) were measured to find average values and variations ((maximum value - minimum value)/average value).
  • thermoelectric thin films as long as they have a bixbite type crystal structure, likewise produced good results even when using a complex oxide composition different from the ones shown in TABLE 4.
  • the formation condition and the heat treatment condition of thermistor thin films are not limited to the conditions shown in the table and can therefore be set in various ways according to the composition of sintered body targets.
  • the oxygen partial pressure is generally high or when there is much Mn in composition (for example, when the Mn composition contained is 55% or more by molar ratio), it is likely that the foregoing bixbite type crystal structure is formed.
  • any other one that partially contains a spinel type crystal phase or an NaCl type crystal phase in a bixbite type crystal phase, can be applicable.
  • the thin film thermistor element 10 of the third embodiment has apparently the same structure as the first embodiment (see FIGURE 1) but differs from the first embodiment in that the thermistor thin film 12 is formed of, for example, LaCoO 3 having a rhombohedral perovskite type crystal structure.
  • the thermistor thin film 12 of such a type can be formed by, for example, the sputter device 21 shown in FIGURE 2, as in the first embodiment.
  • the formation conditions of the thermistor thin film 12 i.e., the condition of sputtering and the condition of heat treatment
  • the formation conditions of the thermistor thin film 12 i.e., the condition of sputtering and the condition of heat treatment
  • thermistor thin films 12 were formed under conditions as shown in TABLE 5. Then, these thermistor thin films 12 thus formed were subjected to heat treatment in air under conditions as shown in the table.
  • alumina substrates sized to have dimensions of 120 mm ⁇ 60 mm ⁇ 0.3 mm and polished to such an extent that their surface irregularity fell below 0.03 ⁇ m, were used as the backing substrate 11.
  • the substrate holder 22 was made to hold, in addition to the backing substrate 11, a glass substrate 31 for the purpose of evaluating crystallinity.
  • a composition for the sintered body target 23 it is possible to form a thermistor thin film 12 having a film composition as shown in the table.
  • EXPERIMENTAL EXAMPLES C1 and C2 each have a rhombohedral perovskite type crystal structure. Further, EXPERIMENTAL EXAMPLES C1 and C2 each have a priority orientation in a (012) surface, whereas EXPERIMENTAL EXAMPLE C3 has no priority orientation, in other words, it is random in orientation.
  • a thin film of Pt having a thickness of 0.1 ⁇ m and a resist pattern were formed all over the surface of the thermistor thin film 12 formed on the backing substrate 11 and then subjected to heat treatment. This was followed by patterning by means of a photolithography technique using dry etching with Ar (argon gas) thereby to form the comb electrodes 13 and 14.
  • Ar argon gas
  • a dicing device was used to cut, at a size of 3.2 ⁇ 1.6 mm, the backing substrate 11 (except its periphery) to prepare 1000 individual thin film thermistor elements 10 having a structure as shown in FIGURE 1 and their respective resistance values and B constants (the change rate of resistance to temperature, B0: the change rates at 0-25 degrees centigrade; B150: the change rates at 25-150 degrees centigrade ) were measured to find average values and variations ((maximum value - minimum value)/average value). The results thereof are shown in TABLE 6.
  • the sintered body was cut at a size of 3.2 ⁇ 1.6 mm to prepare 1000 sintered body thermistor elements and their respective resistance values and B constants (the change rate of resistance to temperature, B0: the change rates at 0-25 degrees centigrade; B150: the change rates at 25-150 degrees centigrade ) were measured to find average values and variations ((maximum value - minimum value)/average value). The results thereof are shown in COMPARE EXAMPLE C of TABLE 6.
  • LaCoO 3 having a rhombohedral perovskite type crystal structure is used as rare earth transition metal oxide for forming the thermistor thin film 12, which is however not considered to be restrictive.
  • rare earth transition metal oxide instead of La, other rare earth elements including Ce, Pr, Nd, Sm, Gd, and Tb are applicable, and instead of Co, other transition metal elements including Ti, V, Cr, Mn, Fe, and Ni are applicable. In both the cases, the same good results were obtained. Furthermore, even when rare earth transition metal oxide contains, as an additive thereto, A1 oxide or Si oxide, the same good results were obtained.
  • the mechanism of resistance-value fine adjustment is described.
  • the comb electrode (13, 14) is provided with the base resistance portion (13a, 14a) and the trimming portion (13b, 14b), wherein a base resistor is formed of a portion defined between the base resistance portions 13a and 14a in the thermistor thin film 12 while on the other hand a resistor for fine adjustment is formed of a portion defined between the trimming portion 13b and each trimming portion 14b.
  • the base resistor and each fine adjustment resistor are connected together in parallel.
  • each fine adjustment resistor differs in resistance value from the other fine adjustment resistors and the resistance value of each of the fine adjustment resistors is set greater than that of the base resistor.
  • the resistance value of the base resistor is set somewhat greater than the target resistance value of the thin film thermistor element 10 and, in addition, it is set such that the base resistor/fine adjustment resistor composite resistance value is lower than the target resistance value by about 10%.
  • the trimming portion 14b is selectively cut, so that the resistance value of the thin film thermistor element 10 can be fine adjusted.
  • an arrangement may be made beforehand in which thermistor thin film patterning is carried out such that the thermistor thin film 12 exists only between each trimming portion 14b and the trimming portion 13b.
  • Such patterning can be implemented by means of masking during formation of the thermistor thin film 12 or by photolithography after the thermistor thin film 12 is formed.
  • each thin film thermistor element 10 is measured.
  • the trimming portion 14b is irradiated with, for example, YAG laser light for selective cutting of the trimming portion 14b. This is followed by cutting the backing substrate 11 at a size of 1 ⁇ 0.5 mm (in the first and second embodiments) and at a size of 3.2 ⁇ 1.6 mm (in the third embodiment), for separation into 1000 individual thin film thermistor elements 10.
  • each thin film thermistor element 10 was measured again to find average values and variations ((maximum value - minimum value/average value). The results are shown in TABLE 7. As TABLE 7 clearly shows, it is possible to obtain much higher-accuracy thermistor elements by performing fine adjustment of the resistance value by trimming a portion of the comb electrode (13, 14) which is a Pt electrode formed on the thermistor thin film 12.
  • EXPERIMENTAL EXAMPLE A1 270k ⁇ /2% 300k ⁇ /300k ⁇ /0.5% EXPERIMENTAL EXAMPLE A2 318k ⁇ /2% 340k ⁇ /340k ⁇ /0.7% EXPERIMENTAL EXAMPLE A3 243k ⁇ /3% 260k ⁇ /260k ⁇ /0.5% EXPERIMENTAL EXAMPLE A4 267k ⁇ /2.5% 290k ⁇ /290k ⁇ /0.6% EXPERIMENTAL EXAMPLE A5 32k ⁇ /2% 35k ⁇ /35k ⁇ /0.7% EXPERIMENTAL EXAMPLE A6 210k ⁇ /3% 230k ⁇ /230k ⁇ /0.8% EXPERIMENTAL EXAMPLE A7 251k ⁇ /2% 270k ⁇ /270k ⁇ /0.5% EXPERIMENTAL EXAMPLE A8 310k ⁇ /2% 340k ⁇ /340k
  • the foregoing resistance-value fine adjustment may be made after separation into the individual thin film thermistor elements 10 (i.e., after the cutting of the backing substrate 11). However, in general it is convenient to perform resistance-value line adjustment before such separation, in terms of handling easiness for resistance-value measurement and for the cutting of the trimming portion 14b.
  • an alumina substrate is used as the backing substrate 11.
  • the same good results were obtainable, even for the case of using a ceramics substrate or glass substrate as the backing substrate 11.
  • Pt is used as electrode material.
  • the same good result were obtained, ever for the case of using palladium, iridium, ruthenium, gold, silver, nickel, copper, chromium, or their alloy as electrode material.
  • the sintered body target 23 used in forming the thermistor thin film 12 by sputtering is not necessarily the above-described, integrally-formed one.
  • the sintered body target 23 in order to form the thermistor thin film 12 which is uniform, it is required that the sintered body target 23 is larger than the film formation area of the thermistor thin film 12 and, in addition, in order to fabricate a large quantity of the thin film thermistor elements 10 at a time, it is preferable to use a target as large as possible (for example, diameter: 10 inches; thickness: 5 mm).
  • a target as large as possible (for example, diameter: 10 inches; thickness: 5 mm).
  • the material of the sintered body target 23 is hard and fragile, it is considerably difficult to perform bonding to the backing plate after sintering in uniform and close manner to a large area.
  • an arrangement as shown in FIGURE 3, may be made in which, for example, LaCoO 3 -oxide sintered body blocks 43 of three kinds of sizes, i.e., 40 ⁇ 40 mm ( ⁇ 5 mm: thickness), 40 ⁇ 20 mm ( ⁇ 5 mm: thickness) and/or 20 ⁇ 20 mm ( ⁇ 5 mm: thickness), are spread all over a Cu backing plate 46 having a diameter of 250 mm at intervals of 0.5 mm and bonding is carried out, and its peripheral portion is covered with an earth shield 47 whose opening portion diameter is 200 mm (in FIGURE 3, the shield cover 24 shown in FIGURE 2 is omitted).
  • the sintered body blocks 43 it becomes possible to easily obtain the thermistor thin film 12 which has a large area and is high in uniformity.
  • a high frequency power supply is used to sputter the thermistor thin film 12, which is however not considered to be restrictive.
  • sputtering may be carried out by creation of a plasma by ECR (electron cyclotron resonance).
  • the way of forming the thermistor thin film 12 is not limited to the foregoing intermittent sputtering.
  • such a thermistor thin film may be formed by continuous sputtering after properly setting film formation conditions. Also in such a case, it is possible to easily improve the uniformity of thermistor thin films by rotating the substrate holder 22 or the sintered body target 23.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Thermistors And Varistors (AREA)
EP00304729A 1999-06-03 2000-06-05 Dünnschichtthermistor und Herstellungsverfahren Expired - Lifetime EP1058276B1 (de)

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JP15662699 1999-06-03
JP15662699A JP4279400B2 (ja) 1999-06-03 1999-06-03 薄膜サーミスタ素子および薄膜サーミスタ素子の製造方法
JP15670899A JP4279401B2 (ja) 1999-06-03 1999-06-03 薄膜サーミスタ素子
JP15670899 1999-06-03
JP15656999 1999-06-03
JP15656999A JP4279399B2 (ja) 1999-06-03 1999-06-03 薄膜サーミスタ素子および薄膜サーミスタ素子の製造方法
JP11161903A JP2000348911A (ja) 1999-06-09 1999-06-09 薄膜ｎｔｃサーミスタ素子およびその製造方法
JP16190399 1999-06-09
JP25522599 1999-09-09
JP25522599A JP4277380B2 (ja) 1999-09-09 1999-09-09 薄膜サーミスタ素子

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WO2003063185A2 (de) * 2002-01-25 2003-07-31 Epcos Ag Elektrokeramisches bauelement mit innenelektroden
CN113072380A (zh) * 2021-03-26 2021-07-06 电子科技大学 一种用于pld的钴酸镧陶瓷靶材及其制备方法与应用

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JP3929705B2 (ja) * 2001-02-05 2007-06-13 ユーディナデバイス株式会社 半導体装置及びチップキャリア
DE10302800A1 (de) * 2003-01-24 2004-08-12 Epcos Ag Verfahren zur Herstellung eines Bauelements
US8523430B2 (en) * 2010-07-28 2013-09-03 Lattron Co. Ltd. Ultra thin temperature sensor device
CN102544137A (zh) * 2012-01-20 2012-07-04 中国科学院上海技术物理研究所 一种基于宝石衬底的宽波段薄膜型光电探测器
US10431357B2 (en) * 2017-11-13 2019-10-01 Texas Instruments Incorporated Vertically-constructed, temperature-sensing resistors and methods of making the same
CN114041194B (zh) * 2019-07-05 2023-08-22 Tdk电子股份有限公司 Ntc薄膜热敏电阻和制造ntc薄膜热敏电阻的方法
CN112509773B (zh) * 2020-10-23 2022-08-12 浙江森尼克半导体有限公司 一种霍尔电流激光调阻机调节设备组件
JP2022089433A (ja) 2020-12-04 2022-06-16 Tdk株式会社 サーミスタ素子及び電磁波センサ

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US7084732B2 (en) 2002-01-25 2006-08-01 Epcos Ag Electroceramic component comprising inner electrodes
CN113072380A (zh) * 2021-03-26 2021-07-06 电子科技大学 一种用于pld的钴酸镧陶瓷靶材及其制备方法与应用
CN113072380B (zh) * 2021-03-26 2022-09-16 电子科技大学 一种用于pld的钴酸镧陶瓷靶材及其制备方法与应用

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US6475604B1 (en) 2002-11-05
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KR20010007148A (ko) 2001-01-26
EP1058276A3 (de) 2004-01-28
EP1058276B1 (de) 2005-10-26

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